The invention relates to attachable couplings of the male stem--ferrule type for use with reinforced, flexible hose, but more particularly, the invention relates to a ferrule with longitudinal ribs formed on its inside surface.
Couplings post assembled to a finished hose product typically have a male stem portion that is insertable into a hose end and a ferrule that is concentric with the male stem. Together, the male stem and ferrule define an annular cavity for receiving a hose end. The coupling is retained by pinching the hose end between the ferrule and stem. This is accomplished by either the effects of radially reducing the size of the ferrule or a radial increase in the male stem.
Sealing and retaining a coupling to a high pressure hose subjected to impulses may be accomplished by using a serrated stem with a ferrule locking collar. The ferrule may be pre-attached such as by crimping an end portion to the collar so that the annular hose receiving cavity is formed or a separate ferrule with an internal collar may be provided to attach behind the stem collar when the ferrule is crimped.
Circumferential or helical ribs or threads are oftentimes provided on the inside of the ferrule to cause undulations in or to make surface contact with a twined hose reinforcement in conjunction with a serrated stem.
The ferrule locking collar, serrated stem, and ferrule with either helical or annular ribs represent techniques used to withstand high end forces while simultaneously providing a coupling hose seal. For example, a coupling for use with a one-half inch (I.D.) hose having an 8,000 psi burst pressure must withstand end forces of approximately 3/4 ton without leaking. Some ferrules using helical or circumferential ribs require the cover to be skived from the hose so the ribs can make direct surface contact with a reinforcement such as braided wire. Other ferrules have sharp annular or helical ribs which cut through the cover and make surface contact with the reinforcement during a crimping operation. In either case, the ferrules are sometimes difficult to install over a flared reinforcement at the hose end when annular or helical ribs of the ferrule circumferentially engage the reinforcement. Also, such ferrules are oftentimes expensive because the ferrule must be turned from bar stock to the desired configuration.
The ferrule of the invention is intended for use with the various types of couplings and the process for making the ferrule eliminates several machining operations.